Is Smartmeter Reading over serial interface recommended?

[binderth (Thomas Binder)]

@STSC

With Tasmota and MQTT?

sorry, for the late answer: not with Tasmota, but with ESPEasy.
But I also have also a whole bunch of Wifi sockets running energy sensors with Tasmota

[binderth (Thomas Binder)]

@STSC

No, e.g. Volkszaehler is doing this. You don’t need a separate datapoint. Reason is that you get the counter value with a very high resolution like 0,xxx kWh. So you only need exact timestamps. I was also surprised, but it is working perfect in Volkszaehler.

with that, you’re depending on the timestamps and that they’re reliable. You can read out the consuption between the timestamps and interpolate the current power.

@STSC

A lot of energy meter only provide 1.8.0 and maybe 2.8.0.

I use(d) the Smartmeter Binding with my “volkszaehler reader” until I changed to tibber and they need the pulse on my digital meter.
But: if you unlocked the digital meter (or even Smartmeter the digital meter with a gateway), you have at least the following endpoints (in OBIS-CODE) available as channels:

• 1.8.0: meter reading (kWh)
• 1.6.0 (or 16.7.0, depending on model): active power (kW)

if the protocol your digtal/smart meter uses is understood by the smartmeter reading (SML like eHZs, Holleys should also use SML), the binding does auto detect those channels.

Which means you’ll get the current power at the time of reading and the current energy and you don’t have to calculate anything.

that is, if you unlocked the meter. My guess is you did not. all digital meters (and smart meters) must provide all the OBIS Codes. But nearly all of them come closed and you have to unlock the interface with a flash light (yes, that’s an interface even in 21st century)

[STSC]

@binderth

all digital meters (and smart meters) must provide all the OBIS Codes

Actually not and this is the problem. The power company decides what is available. There are a lot more,
e.g.
31.7.0 L1 Current
51.7.0 L2 Current
71.7.0 L3 Current
They would be very helpful for load management if you have the current of every single phase.

[binderth (Thomas Binder)]

@STSC

The power company decides what is available.

sorry, I was speaking german law. Don’t know how it is elsewhere, but here in Germany under the “Messstellenbetriebsgesetz (MsbG)” it’s required for digital meters to spit out those numbers. Not the L1/2/3 splits, though. But at least the meter readings and the power. And if you’re on two tariffs (low and high tarif) that also. And feed-in, if you’re having an EEG PV installed.

@STSC

They would be very helpful for load management if you have the current of every single phase.

yes, I agree. But if you’ve got PV installed you probably have your own “smart meter” integrated in your installation (not relevant for your utilities provider, though).